Tin-zirconium alloy and process of making the same



Patented Nov. 4. 1925.

, UNITED STATES- PATENT OFFICE.

HUGH S. COOPER, F CLEVELAND, OHIO, ASSIGhTOR TO KEMET LABORATORIES COH- PANY, INC., A CORPORATION OF NEW YORK.

TIN-ZIROONIUM ALLOY AND PROCESS OF MAKING- THE SAME.

1T0 Drawing.

To all whom it may concern:

Be it known that I, HUGH S. Coornn, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and 5 State of Ohio, have invented certain new and useful Improvements in Tin-Zirconium Alloys and Processes of Making the Same,

of which the following is a specification.

This invention comprises alloys of tin l0 and zirconium, and processes of making the same. It includes also novel and mixtures of finely divided tin and zirconium in alloying proportions, and bodies of pyrophoric tin-zirconium alloy shaped to adapt them for use in'igniters.

Tin and zirconium form alloys having very high melting points, probably above the melting point 0 pure zirconium. The alloys are pyro horic to a high degree, es-

pecially when t ey contain more than about 40% zirconium, and are therefore ada ted for use in igniters such as those which ave heretofore employed cerium alloys.

Because of the very high melting points 35 of tin zirconium alloys, and the avidity with which they unite with oxygen, it is desirable to avoid the necessity of remelting them.

I have found that the alloy may be produced in suitable shapes, without remelting, by the following method:

Zirconium metal in the form of powder or laminae, prepared for example b reducing anhydrous zirconium tetrachloride with metallic sodium, is carefully dried, for example by heating at 6080 C. for several days. In this finel divided form, the metal is very easily oxi ized and tends to ignite spontaneously: to prevent this, it is preferable to evacuate the drying oven.

The thoroughly dry powder is I then pressed into dies under heavy pressure. For example, a rod about ten inches long and one-fourth inch square may be subjected to a pressure of to tons applied in a trans- 5 verse direction. The bodies formed by the method described are comparatively hard and stron The rofs or-the like are next heated in a bath of molten tin. This may be done by 50 packin them in powdered tinin narrow VGIlBlCBf alundum tubes, or by placing them,

surrounded by fragments of tin, in horizontal boatsyand then heating in vacuo until Application filed June 27, 1922. Serial No. 571,284.

the tin melts and alloys with the zirconium. If the tin is present in proper amount, it will be almost completely absorbed, and I have found that the pyrophoric properties are most strongly developed when tin is present in the alloy to the extent of 20% to 40%.

As the temperature is increased, there is a considerable evolution of heat between action and alloyage of the metals. The heating is continued to a temperature of 1500 C. or above to permit the reaction to complete itself, and the furnace is then cooled and the shapes removed.

As an alternative, dry tin powder may be mixed with the thoroughly dry finelydlvided zirconium in the proper proport1ons,.and the mixture pressed into shapes as before. These shapes are then heated in vacuo to- 1500 C. or above without sur rounding them with tin. The evolution of heat takes place between 700 and 1000 C as in the precedin example. 7

By the method escribed, the alloy can be formed into rods, blocks, discs, or any other shape required by a particular type of igniter without remelting the alloy, and without cutting it. It is only necessar to produce coherent bodies of zirconium o the size and shape desired, with or without the necessary tin, and then to cause the zirconium to combine withtin in a non-oxidizing atmosphere.

I claim:

1. An alloy composed of zirconium and tin, each element being present in a substantial amount. 4 v I 2. A pyrophoric alloy containing zircomum" and tin.

3. A pyrophoric alloy containing zirconlum and 20% to 40% of tin.

4. An alloy composed of tin and more than 40% of zirconium.

5. Process of forming a zirconium-tin alloy which comprises heating zirconium in contact with tin at a temperature above 700 C.

6. Process according to claim 5 in which the zirconium and tin in finely divided state are mixed and pressed into compact form before heating.

7. Process of producin a zirconium-tin alloy inbodies of pre etermined form,

700 and 1000 (1., indicating a chemical rewhich comprises pressing a material conand dry zirconium powder in alloying protaining dry finely divided zirconium and portions.

tin into the form desired, and then heating 9. In a pyrophoric igniting device, a

the bodies at a temperature above 700 sparking element formed of a tin-zirconium 5 0., in absence of substantial quantities of alloy.

oxygen. In testimony whereof, I aflix my signature.

8. A composition suitable for making yrophoric alloys containing dry tin pow er HUGH S. COOPER. 

